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From:   Alexandru Tachici <alexandru.tachici@analog.com>
To:     <linux-kernel@vger.kernel.org>
CC:     <andrew@lunn.ch>, <linux@armlinux.org.uk>, <davem@davemloft.net>,
        <edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
        <netdev@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <robh+dt@kernel.org>
Subject: [net-next 1/2] net: ethernet: adi: adin1110: add reset GPIO
Date:   Wed, 19 Oct 2022 20:13:13 +0300
Message-ID: <20221019171314.86325-1-alexandru.tachici@analog.com>
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Add an optional GPIO to be used for a hardware reset of the IC.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/net/ethernet/adi/adin1110.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/net/ethernet/adi/adin1110.c b/drivers/net/ethernet/adi/adin1110.c
index 78ded19dd8c1..3e090ff9b966 100644
--- a/drivers/net/ethernet/adi/adin1110.c
+++ b/drivers/net/ethernet/adi/adin1110.c
@@ -1082,9 +1082,30 @@ static void adin1110_adjust_link(struct net_device *dev)
  */
 static int adin1110_check_spi(struct adin1110_priv *priv)
 {
+	struct gpio_desc *reset_gpio;
 	int ret;
 	u32 val;
 
+	reset_gpio = devm_gpiod_get_optional(&priv->spidev->dev, "reset",
+					     GPIOD_OUT_LOW);
+	if (reset_gpio) {
+		/* MISO pin is used for internal configuration, can't have
+		 * anyone else disturbing the SDO line.
+		 */
+		spi_bus_lock(priv->spidev->controller);
+
+		gpiod_set_value(reset_gpio, 1);
+		fsleep(10000);
+		gpiod_set_value(reset_gpio, 0);
+
+		/* Need to wait 90 ms before interacting with
+		 * the MAC after a HW reset.
+		 */
+		fsleep(90000);
+
+		spi_bus_unlock(priv->spidev->controller);
+	}
+
 	ret = adin1110_read_reg(priv, ADIN1110_PHY_ID, &val);
 	if (ret < 0)
 		return ret;
-- 
2.34.1